Safety closure cap for containers

ABSTRACT

There is disclosed a safety container closure attachable to the neck of a container or to a tubular base secured to the container. The safety closure comprises a screw cap which can be screwed off or on and constitutes the closure proper and a cover cap rotatably fitted upon the screw cap completely overlying the screw cap to prevent direct access to the same. The cover cap is normally biased into a position spaced apart from the screw cap so that rotation of the cover cap has no effect on the screw cap but can be axially depressed into a position in which it is coupled to the screw cap. With the cover cap in this coupling position, rotation of the cover cap causes rotation of the screw cap also thereby permitting opening or closing of the container.

United States Patent [191 Costa [111 3,817,416 June 18, 1974 SAFETY CLOSURE CAP FOR CONTAINERS [52] US. Cl 215/9, 215/46 A, 222/153 [51] Int. Cl. A61j l/00, 865d 55/02 [58] Field of Search 215/9, 46 A; 222/153 [56] References Cited UNITED STATES PATENTS l/l970 Marcel ..222/153 9/1972 Mumford ..2l5/9 Primary Examiner-George T. Hall Attorney, Agent, or Firm-He ne,- Baxley'& Spiecens [57] ABSTRACT There is disclosed a safety container closure attachable to the neck of a container or to a tubular base secured to the container. The safety closure comprises a screw cap which can be screwed off or on and constitutes the closure proper and a cover cap rotatably fitted upon the screw cap completely overlying the screw cap to prevent direct access to the same. The cover cap is normally biased into a position spaced apart from the screw cap so that rotation of the cover caphas no effect on the screw cap but can be axially depressed into a position in which it is coupled to the screw cap. With the cover cap in this coupling position, rotation of the cover cap causes rotation of the screw cap also thereby permitting opening or closing of the container.

21 Claims, 15 Drawing Figures Z9 Z8 3/ L9 6 I] //l I I 37 /,Z/ 2 I f/: 2274/ 22 1 7 2 3g I y I 37 3.4- 7 /0 /7\ /2 II v V II /3 i PATENTEDJuu 18 m4 SHEET 2 BF 3 FIG. 9

SAFETY CLOSURE CAP FOR CONTAINERS The invention relates to a safety container closure cap, which includes a screw cap screwable on the neck of the container, or into a base part secured to the neck.

BACKGROUND With container closures of this kind as now known, the screw cap is directly accessible to the user of the container and is generally screwed off by turning it in counterclockwise direction and screwed on by turning it in clockwise direction.

Such simple mechanisms entail danger that even young children are able to open the container closure and thus obtain access to the content thereof. This may result in injuries and even poisoning of children.

THE INVENTION It is an object of the invention to provide a container closure cap such that it can be screwed off and on whenever desired, but that in particular the screwing off is not possible by simply turning a cap accessible from the outside but that a combination of manipulative steps is required whereby the danger of opening of the container closure by children is very much reduced.

Another'more specific object of the invention is that for opening and reclosing of the container no additional devices such as special tools are required.

SUMMARY OF THE INVENTION The objects of the invention are obtained by providing a container closure of the kind hereinbefore referred to, the screw cap of which can be turned only .when moved into coupling engagement with an axially displaceable cover cap accessible from the outside and overlying the screw cap. As a result of this arrangement, screwing off and on the container closure requires that simultaneously with the turning of the cover cap in axial displacement of this cap is effected. Such displacement couples the cover cap with the screw cap, thereby transferring the rotational movement of the cover cap to the screw cap itself.

The invention also provides that only the cover cap which completely covers the screw cap, is accessible to the grip of the user; in other words, a direct access to the screw cap which requires a rotational movement is prevented. In this manner, it is assured that only by simultaneous axial and rotational movement of the cover cap operation of the actual closure component as represented by the screw cap is made possible. The likelihood of simultaneously effecting these two movements by a young child playing with a container equipped with the safety closure cap of the invention is minimal, so that a highly effective safety closure is provided. The cover cap is advantageously arranged on the screw cap so that it can not be lost, for instance, by providing an inner annular rib on the cover cap underlying a rim of the screw cap or protrusions thereon so that direct access to the screw cap by pulling off the cover cap is not possible.

Coupling of the cover cap with he screw cap by an axial movement of the caps relative to each other can be effected in accordance with the invention by complementary protrusions and depressions on the caps which engage each other in response to axial displacement of the cover cap with reference to the screw cap but are otherwise disengaged so that the cover cap is freely turnable about the screw cap.

To assure that the cover cap and the screw cap are normally not in coupling engagement so that a turning of the cover cap does not cause a corresponding turning of the screw cap and thus the container closure can not be opened, it is provided according to a further aspect of the invention that elastic members bias the cover into the disengaged position and that only by overcoming the action of these elastic members by axial pressure the cover cap can be moved into the coupled position. Elastic members between the bottom of the closure cap and the bottom of the screw cap may comprise flexible ribs, for instance, inthe form of slotted rings which are integral with the cover cap and are faced by disc-shaped bosses on the screw cap.

With a container closure cap according to the invention the actual closure member as formed by the screw cap can be directly screwed on external threads on the outside of the container such as the neck of the container. According to a further embodiment of the invention, which is of particular advantage, a base part is provided which comprises an upper threaded part integral with a receiving lower part. This lower part is fittable by means of an annular groove on the rim of the container neck overlying the same.

The invention also provides that the base part is rigidly but detachably mounted on the neck of the container constituting part thereof. The part has an external thread fitting the inner thread of the screw cap. This has the advantage that by selecting a suitable configuration of the base part the same screw cap can be used for containers which are differently shaped, especially as to the width of the neck.

The base part can be so arranged that it can be fitted into an opening of a container wall such as the top and then constitutes a neck for the same. Of course, the attachment of the base part to the container must be such that the base part can not be turned as otherwise the screwing off and on of the container closure by moving the cover cap and the screw cap into the coupling position and subsequent turning of both caps would not be effective.

To mount a container closure on a container which has already a neck portion, it is advantageous when the base part comprises a cylindrical threaded upper portion and a lower portion including an annular groove which can be fitted upon the rim of the neck of the container overlying the same.

The base part constitutes a substitute for the upper threaded section on the neck of the container for screwing thereon the screw cap and this has the advantage that the cover cap and the screw cap do not have to be conformed to the dimensions of the neck of the specific container but that such adaption of the specific dimension can be effected by merely shaping the base part accordingly.

To effect a rigid and in particular not rotatable connection between the receiving portion of the base part and the neck of a container it is possible to provide at the lower rim of the receiving portion, preferably on both sides in the ring-shaped grooves radially engaging snap rings which engage corresponding counter snap rings at the upper rim of the neck of the container.

It is advantageous to provide for this purpose that an annular rib on the inner wall of the ring-shaped groove engages an annular rib protruding into the neck opening of the container while on the oppositely disposed outer wall of the annular groove in the base part protrusions are provided which can engage with grooves provided on the upper rim of the neck of the container. The base part preferably has a substantially h-shaped lengthwise cross-section so that a configuration is possible in which the outer diameter of the cover cap corresponds to the outer diameter of the receiving portion of the base part.

To make it difficult for a child to open a container closure according to the invention which has not been previously opened and also to assure the user of the container that the same has not been opened before,

the container closure according to the invention can be so arranged that the cover cap can be moved into the coupling position only after tearing off a strip disposed between the closure cap and the base part or neck of the container.

When the afore referred to base part has the substantially h-shaped cross-section, the tear or pull strip is advantageously disposed between the cover cap and the outwardly facing side of an annular shank of the base part. This base part constitutes for all practical purpose part of the container neck.

To prevent that the tear strip can be made ineffective by merely bending it outwardly, the strip is preferably provided with protrusions on its inner side which engage depressions in the annular shank of the base part. With such arrangement, it is assured that only by tearing off the strip the cover gap can be moved into the coupling position with the screw cap. Hence, only after removal of the strip opening of the container closure is possible.

BRIEF DESCRIPTION OF THE INVENTION Further advantages, featuresand details of the invention will become apparent from the subsequent description of several embodiments according to the invention.

In the drawings:

FIG. 1 is an elevational cross-section of the upper part of a container having a neck portion seating a safety container closure cap according to the invention on a greatly enlarged scale;

FIG. 2 is a section along Line IIII of FIG. 1 of the base part on a reduced scale;

FIG. 3 is an elevational section of a further reduced view taken on Line IIIIII of FIG. 2;

FIG. 4 is a perspective view of a cover cap with a tear-off strip according to FIG. 1 as seen at a slant from below;

FIG. 5 is an axial cross-section of the cover cap according to FIG. 4;

FIG. 6 is a section taken on Line VI-VI of the cover cap according to FIG. 5;

FIG. 7 is aperspective viewf the screw cap as used in FIG. 1; and

FIGS. 8, 9, 10, ll, 12, l3, l4 and are modifications of FIGS. 1 to 7 with respect to the cover cap and the screw cap associated therewith.

FIG. 1 shows a container 1 upon the neck 2 of which a generally tubular base part 3 is fitted. The upper cylindrical threaded portion 4 of part 3 has screwed thereupon a screw cap 6 which is overlapped by a cover cap 5. The base part 3 is further provided with a lower receiving portion 7 which by means of an annular. groove 8 is clamped upon the rim neck 2. Part 3 serves for adaption of screw caps 6 which have the same size to containers the necks 2 of which have different diameters. Obviously, it is easier and less expensive to produce by injection molding of a suitable synthetic plastic correctly dimensioned base parts than to provide, for instance, screw caps 6 for each size of the neck diameter thereby keeping low the inventory of screw caps 6. Each size 'of screw caps also requires appropriately dimensioned cover caps 5. Moreover, it is not necessary to provide on the outside of neck 2 threads for screwing thereupon the screw caps 6.

The annular groove 8 of part 3 defines an inner annular wall 9 and a concentric outer wall 10, the outer wall being longer than the inner wall. Both these walls extend in axial direction and are joined by a horizontally disposed base wall 11 thereby defining and closing off the top side of the groove.

When the base part 3 is slipped on neck 2 of container 1, the neck extends into groove 8 and abuts with its top rim 12 on the inside of base wall 11. The inner ring wall 9 has at its lower end an inwardly protruding bead 13 which is in engagement with a peripheral rib 15 formed in the neck opening 14 near the upper rim of neck 2. The inner surface of the outer wall 10 is formed with protrusions 16 engageable with correspondingly shaped recesses 17 distributed over the circumference of the neck. The recesses 17 are closed at the upper and the lower end by an annular rib 18. The springy or elastic engagement of annular bead 13 of the base part with the annular rib 15 on the neck and engagement of the protrusions 16 in the depressions 17 of the neck effect a rigid mounting of the base part to neck 2 as movement in axial direction and in circumferential direction is prevented by wall 11 and protrusions 16 respectively.

The screw cap 6 has on the inside of its bottom wall 19 an annular rib 20 which serves to rigidify the bottom of the screw cap and also to improve the sealing. The screw cap has further a threaded side wall 24 which overlies the cylindrical upper threaded portion 4 of base part 3. A wall 21 of the screw cap has an inner thread 22 engaged with the outer thread of threaded upper portion 4 of base part 3.

To effect coupling of cover cap 5 with screw cap 6, which is not accessible from the outside, so that the screw cap can be turned for screwing off and on cap 6 from portion 4 of base part 3, there are provided on the screw cap at the lower end thereof outwardly protruding ribs 24 forming a toothed ring and circumferentially spaced grooves 25 on the outer edge of the screw cap bottom 19. These ribs 24 and grooves 25 coact with the cover cap wall 26 by means of inwardly protruding counter ribs 27 forming an inner ring and also with corresponding counter ribs 29 disposed at a slant at the edge between the cover cap wall 26 and the cover cap bottom 28. To prevent a pulling off of the cover cap 5 in outward direction from the screw cap the cover cap 6 is provided with an inner annular rib 30 which underlies tooth-shaped ribs 24.

On the inside of the bottom 28 of the cover cap there are provided flexible protrusions 31 forming slotted rings. Disc-shaped bosses 32 on the outside of the screw cap bottom 19 face protrusions 31 for coaction therewith.

Protrusions 31 retain the bottom 28 of the cover cap at a selected distance from the bottom of the screw cap. As a result, the ribs 27 and 29 on the cover cap can be moved into the Coupling position with the detents on thescrew cap as formed by ribs 24 and grooves 25 only by application of axial pressure upon the cover cap.

Prior to the first opening of the container, that is, when the container is still in the condition in which it has been bought, there is provided between the cover cap 5 and the ring-shaped bottom or shank ll of the base part 3 a tear-off strip 33 which preferably has along its lower edge protrusions 34 engaging depressions 35 in base part 3. To effect opening of the initially positively locked container strip 33 which is joined by a narrow bridge 36 to the cover cap is torn off by pulling a tab 37.

After removal of strip 33 the cover cap by an axial pressure applied thereto can be pushed downwardly against the action of elastic protrusions 31. As a result, the inner detents on the closure cap engage with the respective detents of the screw cap. By maintaining such axial pressure while turning the cover cap such turning is transmitted to the screw cap 6 thereby opening the container. It should be mentioned in this connection 'that it is of course also possible and sufficient to use merely toothed rings formed by the ribs and counter ribs 24 and- 27 respectively for coupling the cover cap 5 to the screw cap 6. Similarly, the ribs 29 on the cover cap and the groove 25 on the screw cap may be used to effect coupling between the caps 5 and 6 by the afore described axial displacement of the cover cap.

The base part 3, the screw cap 6 and the cover cap 5 are preferably produced by ejection molding of a suitable conventional synthetic plastic material while container I may be made of glass, synthetic plastic or metal.

Striations, grooves or ribs 38 on the outside of cover cap wall 26 may be provided to prevent slipping of the hand of the user when depressing and turning cover cap FIGS. 8 and 9 show an exemplification of a cover cap 5 and the associated screw cap 6 respectively in which the elastic protrusions 31 on the inside of the bottom 28 of the screw cap are replaced by an annular rib 31 concentric with the wall 26 of the cover cap. A single disc-shaped boss 32 is disposed opposite to this annular rib on the outside of the bottom 19 of the screw cap.

The slanted ribs 29 in the space between the cover cap wall 26 and the bottom 29 of this cap nd the associated grooves 25 on the circumference of the screw cap bottom 19 are disposed in the embodiment according to FIGS. 8 and 9 in the same manner as in theembodiment according to FIGS. 1 to 7. However, while the second row of grooves and ribs in the arrangement according to FIGS. 1 to 7 are in form of complementary toothed rings, FIGS. 8 and 9 show block-shaped ribs 24 on the outside of screw cap wall 21. These ribs 24' coact with narrow ribs 27 on the inside of the cover cap wall 26. These ribs 27' abut against the sides of ribs 24' in response to an axial displacement of the cover cap relative to the cover cap against the resilient action of the ring 31 so that a turning of cover cap 5 is again transferred to screw cap 6.

The container closure according to the invention due to the necessity of simultaneously applying axial pressure and rotational force to the cover cap provides an effective safety factor against opening of the container by a'child as without the axial pressure on the cover cap the same will idly turn on the screw cap, that is. without transferring such turning to the screw cap. Moreover. if only the axial pressure is applied to the cover cap without a simultaneously rotary force the cover cap will immediately return into the condition in which it is disengaged from the screw cap where thepressure is released. In other words, it is assured that during the entire opening operation the cover cap must be subjected to both axial pressure and rotational force.

The embodiments according to FIGS. 10 to 15 are generally similar to the embodiments of FIGS. 8 and 9 in that they comprise upper ribs 29 on the inside of cover cap 9 and grooves on the outside of the bottom 19 of the screw cap which only after overcoming the counter action of annular rib 31' can engage each other to couple cover cap 5 and screw cap 6 for joint rotation. In addition, the embodiments according to FIGS. 10 to 15 comprise on the outside of the screw cap wall 21 and on the inside of cover cap wall 26, coacting elements which engage each other without axial displacement of the cover cap 5 toward the screw cap 6 when the container closure is screwed on the container to effect a tight sealing of the container. When the cover cap is turned in the opposite direction, that is, in the direction for opening the container closure, these elements slide past each other without engagement.

The protrusions corresponding to the ribs 27 in FIG. 8 are provided in the embodiment of FIG. 10 in the form of ribs 39 which are tapered and undercut in circumferential direction to form wedge-shaped tips 41. Ribs 40 on the screw cap are correspondingly shaped in that they are also wedge-shaped in circumferential direction. As shown in FIG. 11, the ribs 40 have moreover on the most outwardly protruding side a wedgeshaped notch 42. In the spaced-apart position of the caps as caused by the elastic annular rib 31' shown in FIG. 10 the wedge-shaped tips 41 of ribs 39 can engage the wedge-shaped notches 42 when the cover cap is turned in clockwise direction for coupling the cover cap 5 and the screw cap 6 so that the container closure can be screwed tight without requiring axial displacements of the cover cap 5 relative to the screw cap 6 as it is required for the opening of the container closure. In this manner, the more complex manipulation provided as the safety feature is not needed for the closing I of a container closure. Such simplification is justified as the danger factor residesin the opening of the container by a child rather than in the closing thereof.

When the cover cap 5 according to FIG. 10 is turned relative to screw cap 6 according to FIG. 11 in counterclockwise direction, the protrusion 39 and 40 slide relative to each other without causing turning of the screw cap. However, opening of the container closure is possible only when the cover cap 5 is axially depressed simultaneously with turning of the cover cap in counterclockwise direction so that the ribs 29 engage the grooves 25 thereby coupling the cover cap 5 and the screw cap 6 to each other.

In the embodiment of FIGS. 12 and 13 protrusions 29 on the cover cap 5 are wider in axial direction than the corresponding protrusions in FIG. 10. Moreover, they are not pointed or tapered at the tip. The counter protrusions 40 on cover cap 6 according to FIG. 13 also do not include the previously described wedge-shaped grooves. The container closure according to FIGS. 12 and 13 otherwise functions in the same manner as the closure according to FIGS. and 11, that is, closing of the container is possible without axial movement of cover cap 5 relative to cover cap 6. However, opening of the container requires the axial displacement of both caps simultaneously with the turning of cover cap 5 as a safety feature to prevent opening of the closure by a child.

According to FIGS. 14 and 15, cover cap has radially protruding and axially slanted ribs 43 and screw cap 6 has correspondingly shaped and located coating ribs 44. Ribs 43 and 44 constitute incomplete threads which effect coupling of the caps in response to a turning in clockwise direction only for closing the closure while opening requires a combined axial and rotational operation of the cover cap as described.

The invention is not limited to the illustrated and described embodiments. In addition to the various different arrangements of the coacting grooves and protrusions for effecting coupling of the cover cap 5 to the screw cap 6 as described and illustrated, it is also possible to provide a decoupling position between the cover cap and the screw cap so that for coupling the cover cap to the screw cap the cover cap must be pulled upwardly relative to the screw cap while the exemplified embodiments require an axial depression of the cover cap.

It is also possible to provide a container closure according to the invention in conjunction with a nozzle made of a suitable synthetic plastic for a container that does not have a neck portion, that is, of the kind shown in U.S. Pat. No. 3,388,842. Finally, it is also possible as a simple solution of the inventive concept to provide a counter thread for he screw cap 6 directly on the outside of the neck of a container in which case the base part 3 is eliminated. Moreover, the term screw cap is not limited to caps having internal thread engageable with external threads on the base part or the neck itself but is intended to encompass also caps that are attachable by other types of rotary fastening means such as a bayonnet lock.

What is claimed is:

1. A closure device for selectively opening and closing a container, said device comprising in combination:

a tubular inlet and outlet member secured at one end on the container to be opened or closed;

a screw cap screwable off and on the other end of said member for opening or closing said other end;

a cover cap rotatably fitted upon said screw cap; and

.coacting coupling means on the screw cap and the cover cap, said cover cap being axially displaceable into and out of a position of engagement of said coupling means;

said cover cap being rotatable relative to said screw cap when the coupling means are disengaged and being rotatable in unison with the screw cap upon displacement of the cover cap into the axial position in which the coupling means are engaged to effect screwing off or on of the screw cap.

2. The closure device according to claim 1 wherein said cover cap covers the screw cap substantially completely to prevent direct access from the outside to the screww cap.

3. The closure device according to claim 1 wherein retaining means are provided on the cover cap and on the screw cap to prevent separation of the two caps.

4. The closure device according to claim 3 wherein said retaining means comprise a protrusion on an inner sidewall portion of the cover cap and a coacting protrusion on the outside of the sidewall of the screw cap, said protrusion on the cover cap underlying the protrusion on the screw cap thereby preventing pulling off of the cover cap.

5. The closure device according to claim 4 wherein said protrusion on the cover cap is in the form of an annular rib underlying the rim of the sidewall of the screw cap.

6. The closure device according to claim 1 wherein said coupling means comprise protruding ribs and complementary grooves on the inside and the outside of the cover cap and the screw cap respectively.

7. The closure device according to claim 1 and further comprising yieldable means interposed between said caps, said yieldable means biasing the two caps into a spaced-apart position in which said coupling means are disengaged and being arranged to yield for axial displacement of the cover cap into the position in which the coupling means are engaged by applying pressure to the outside of the bottom wall of the cover cap.

8. The closure device according to claim 7 wherein said yieldable means comprise at least one elastic member on the inside of the bottom wall of the cover cap and at least one elastic member on the outside of the bottom wall of the screw cap.

9. The closure cap according to claim 8 wherein the elastic members on the caps are integral with the respective bottom wall.

10. The closure device according to claim 8 wherein the elastic member on the cover cap is in the form of at least one slotted ring and the elastic member on the screw cap is in the form ofa disc-shaped protrusion disposed opposite to said ring for coaction therewith.

11. The closure device according to claim 1 wherein said tubular member constitutes a neck part of the container.

12. The closure device according to claim 1 wherein said tubular member comprises a base part rigidly attachable to the container, said base part having external threads and said screw cap having on its sidewall internal threads engageable with the threads on the base part for screwing the screw cap to the base part.

13. The closure device according to claim 12 wherein said base part comprises an upper portion having thereon said external threads and a lower portion having in its rim an annular groove defining two shanks, said shanks being fittable upon the rim of a neck part of a container.

14. The closure device according to claim 13 and comprising a container with a neck part thereon, and wherein at least one of said shanks has on its inside a protrusion, and wherein the neck part of the container has an outwardly extending protrusion engageable with said protrusion on the shank in overlying relationship for locking the base part to the neck part of the container.

15. The closure device according to claim 14 wherein said neck part has adjacent to its rim an outwardly protruding annular rib, and wherein the inner shank defining the groove in the base part is of a length such that it extends past said rib and has on its inner side an in wardly protruding annular rib underlying said rib on the neck part when the base part is fitted upon he neck part.

16. The closure device according to claim 1 wherein the cover cap has on the inside of its sidewall protrusions and the screw cap has on the outside of its sidewall protrusionst said protrusions being disposed and shaped to coact with each other when the cover cap is in the position in which the coupling means are disengaged for rotating the cover cap for unison with the screw cap in the direction for screwing the screw cap tightly upon the tubular member and for sliding relative to each other upon rotation of the cover cap in the direction for unscrewing the screw cap from said tubular member.

17. The closure device according to claim 1 wherein a tear-off strip is interposed between the cover cap and the screw cap so as to prevent prior to removal of the tear-off strip axial displacement of the cover cap into the position in which the coupling means are engaged.

18. The closure device according to claim 17 wherein said tear-off strip encompasses the caps and is along one of its circumferential edges tearably secured to the cover cap the other circumferential edge against the tubular member for preventing axial displacements of the cover cap relative to the screw cap.

19. The closure device according to claim 17 wherein said tear-off strip has along said other edge a plurality of protrusions and wherein said tubular member has on its outside recesses engageable with said protrusions on the tear-off strip.

20. The closure device according to claim 18 wherein said tear-off.strip and said cover cap are circumferentially secured to each other by a tearable bridge between said cap and the tear-off strip.

21. The closure device according toclaim 1 wherein the outside of the sidewall of the cover cap is roughened to facilitate gripping of the cover cap. 

1. A closure device for selectively opening and closing a container, said device comprising in combination: a tubular inlet and outlet member secured at one end on the container to be opened or closed; a screw cap screwable off and on the other end of said member for opening or closing said other end; a cover cap rotatably fitted upon said screw cap; and coacting coupling means on the screw cap and the cover cap, said cover cap being axially displaceable into and out of a position of engagement of saiD coupling means; said cover cap being rotatable relative to said screw cap when the coupling means are disengaged and being rotatable in unison with the screw cap upon displacement of the cover cap into the axial position in which the coupling means are engaged to effect screwing off or on of the screw cap.
 2. The closure device according to claim 1 wherein said cover cap covers the screw cap substantially completely to prevent direct access from the outside to the screww cap.
 3. The closure device according to claim 1 wherein retaining means are provided on the cover cap and on the screw cap to prevent separation of the two caps.
 4. The closure device according to claim 3 wherein said retaining means comprise a protrusion on an inner sidewall portion of the cover cap and a coacting protrusion on the outside of the sidewall of the screw cap, said protrusion on the cover cap underlying the protrusion on the screw cap thereby preventing pulling off of the cover cap.
 5. The closure device according to claim 4 wherein said protrusion on the cover cap is in the form of an annular rib underlying the rim of the sidewall of the screw cap.
 6. The closure device according to claim 1 wherein said coupling means comprise protruding ribs and complementary grooves on the inside and the outside of the cover cap and the screw cap respectively.
 7. The closure device according to claim 1 and further comprising yieldable means interposed between said caps, said yieldable means biasing the two caps into a spaced-apart position in which said coupling means are disengaged and being arranged to yield for axial displacement of the cover cap into the position in which the coupling means are engaged by applying pressure to the outside of the bottom wall of the cover cap.
 8. The closure device according to claim 7 wherein said yieldable means comprise at least one elastic member on the inside of the bottom wall of the cover cap and at least one elastic member on the outside of the bottom wall of the screw cap.
 9. The closure cap according to claim 8 wherein the elastic members on the caps are integral with the respective bottom wall.
 10. The closure device according to claim 8 wherein the elastic member on the cover cap is in the form of at least one slotted ring and the elastic member on the screw cap is in the form of a disc-shaped protrusion disposed opposite to said ring for coaction therewith.
 11. The closure device according to claim 1 wherein said tubular member constitutes a neck part of the container.
 12. The closure device according to claim 1 wherein said tubular member comprises a base part rigidly attachable to the container, said base part having external threads and said screw cap having on its sidewall internal threads engageable with the threads on the base part for screwing the screw cap to the base part.
 13. The closure device according to claim 12 wherein said base part comprises an upper portion having thereon said external threads and a lower portion having in its rim an annular groove defining two shanks, said shanks being fittable upon the rim of a neck part of a container.
 14. The closure device according to claim 13 and comprising a container with a neck part thereon, and wherein at least one of said shanks has on its inside a protrusion, and wherein the neck part of the container has an outwardly extending protrusion engageable with said protrusion on the shank in overlying relationship for locking the base part to the neck part of the container.
 15. The closure device according to claim 14 wherein said neck part has adjacent to its rim an outwardly protruding annular rib, and wherein the inner shank defining the groove in the base part is of a length such that it extends past said rib and has on its inner side an inwardly protruding annular rib underlying said rib on the neck part when the base part is fitted upon he neck part.
 16. The closure device according to claim 1 wherein the cover cap has on the inside of its sidewaLl protrusions and the screw cap has on the outside of its sidewall protrusions, said protrusions being disposed and shaped to coact with each other when the cover cap is in the position in which the coupling means are disengaged for rotating the cover cap for unison with the screw cap in the direction for screwing the screw cap tightly upon the tubular member and for sliding relative to each other upon rotation of the cover cap in the direction for unscrewing the screw cap from said tubular member.
 17. The closure device according to claim 1 wherein a tear-off strip is interposed between the cover cap and the screw cap so as to prevent prior to removal of the tear-off strip axial displacement of the cover cap into the position in which the coupling means are engaged.
 18. The closure device according to claim 17 wherein said tear-off strip encompasses the caps and is along one of its circumferential edges tearably secured to the cover cap the other circumferential edge against the tubular member for preventing axial displacements of the cover cap relative to the screw cap.
 19. The closure device according to claim 17 wherein said tear-off strip has along said other edge a plurality of protrusions and wherein said tubular member has on its outside recesses engageable with said protrusions on the tear-off strip.
 20. The closure device according to claim 18 wherein said tear-off strip and said cover cap are circumferentially secured to each other by a tearable bridge between said cap and the tear-off strip.
 21. The closure device according to claim 1 wherein the outside of the sidewall of the cover cap is roughened to facilitate gripping of the cover cap. 